The chemical name of Teriflunomide is 2-cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide and formula is C12H9F3N2O2 and molecular weight is 270.207.
Teriflunomide is used as Immunosupressant. It acts as tyrosine kinase inhibitor. It is used in treatment of rheumatoid arthritis, autoimmune disease and multiple sclerosis.
Teriflunomide was first disclosed and claimed in U.S. Pat. No. 5,679,709 but this application does not mention the process of preparation.
U.S. Pat. No. 5,494,911 discloses a process for preparation of Teriflunomide in Example-4 as shown in given below scheme-I

The process involves reacting 5-methylisoxazole-4-carbonyl chloride (V) with 4-trifluoromethylaniline (IV) in acetonitrile to give leflunomide (VI). The subsequent hydrolysis with aqueous sodium hydroxide solution in methanol gives Teriflunomide (I).
U.S. Pat. No. 5,990,141 discloses a process for preparation of Teriflunomide as shown in given below scheme-II.

The process involves reacting 4-trifluoromethyl aniline (IV) with cyanoacetic acid ethyl ester (II) to give cyanoacet-(4-trifluoromethyl)-anilide (VII). This compound is further reacted first with sodium hydride in acetonitrile and then with acetylchloride in THF to give Teriflunomide (I).
U.S. Pat. No. 6,365,626 discloses a process for preparation of Teriflunomide in FIG. 19 which is as given in below scheme-III.

The process involves reacting 4-trifluoromethyl aniline (IV) with cyanoacetic acid (IIa) to give compound of formula (VII). This compound is further reacted first with sodium hydride and then with acetylchloride to give Teriflunomide (I)
All the above mentioned process requires chromatographic purification which in turn results in low yield.
It is therefore, a need to develop a process which not only overcomes the disadvantages of prior art but also be economical, operationally simple and industrially applicable.
Present inventors have directed their research work towards developing a process for the preparation of Teriflunomide which is devoid of the above mentioned disadvantages. The present inventor developed a novel process which not only reduce number of steps of reaction but is also feasible at commercial scale.